by Rick Homer
There are many styles of Port wine but they all start out the same way. Port is a fortified wine that originated in the Douro valley in northern Portugal. It is typically made with Red wine grapes but it can be made in a white style. The best known red grape varietals that are used to make Port in Portugal are Touriga Francesa, Touriga Nacional, Tinta Roriz, Tinta Barroca, Tinta Amarela and Tinto Cão but in total there are around thirty types of Port grape. The wine is produced and then fortified with a neutral alcohol of 77% before the fermentation is finished. This addition of alcohol raises the overall alcohol level to 18% to 20% which inhibits yeast action and results in an off dry to sweet wine which is called Port. This Port is then put into neutral used barrels for aging.
Making Port style wine in North America.
We do not have easy access to the grape varietals that are typically used for making Port in Portugal, however we do have access to Zinfandel which makes a very good Port style wine. I have experimented with fruit and most of the other grape varietals that we have access to, but I have found that the Zinfandel grapes make the best port by far.
What you will need to make port
For every 23 liters of port style wine you wish to make you will need the following;
- 100 lbs of good quality Zinfandel grapes
- 5 grams of D80 yeast
- 5 grams of Go-Ferm
- Yeast Nutrient, Fermaid K or Fermaid O
- 4 liters of alcohol which is 80% or higher.
- A small suitably sized neutral barrel for aging. Make enough port wine to fill the barrel that you have and also allow for topping up each month.
I am not going to go into great detail on how to make wine as you should know how to do this before attempting to make port.
- Crush and destem the Zinfandel grapes and place them into a fermentation vessel. Check the specific gravity of the must and determine from the hydrometer what the Starting potential alcohol content of the must will be if the must was fermented to dryness and record this number. This number will be used in the Pearson Square formula as described later on.
- Rehydrate the D80 yeast with the Go-Ferm. D80 yeast is recommended because it does not have a high alcohol tolerance and it also enhances the varietal characteristics of the Zinfandel grapes. If a high alcohol tolerant yeast is selected such as EC1118 then it will be difficult to stop the fermentation process when you want to.
- Monitor the fermentation process and keep detailed records of the date, time and specific gravity for each measurement. The Specific gravity will begin to rapidly drop as you get close to our end goal of a Specific gravity of 1.030. There is typically only about a 1-2 hour window that you will have to press the must to keep it within this window. I use a graph to predict the time when I need to press the grapes. Note that this could be in the middle of the night and if you wait until the morning you will not have enough residual sugar to make a good port. Pressing the must at a Specific gravity of 1.030 is highly recommended for your first port. This can be modified slightly for subsequent batches to adjust for individual tastes regarding the sweetness level. Record the Ending potential alcohol value from the hydrometer and record this value.
- Using the Pearson square formula will determine the amount of alcohol that needs to be added to the must to bring the alcohol level up to 19%.
The Pearson’s Square can be used to calculate the volume of alcohol that needs to be added to a solution (must/wine) to achieve the desired final alcoholic strength.
X = is the final desired alcohol concentration (19.0%v/v)
A = alcohol concentration (%v/v) of the must/wine to be fortified This is the Starting alcohol potential minus the Ending alcohol potential. (7.5 %v/v)
C = the alcoholic strength/concentration of the fortifying spirit (85.0%v/v)
D = the difference between X and A (19.0 – 7.5 = 11.5)
B = the difference between C and X (85.0 – 19.0 = 66.0)
i.e. for 23 L of must/wine add 23L * 1/5.74 = 4LThen the volume ratio of the fortifying spirit to must/wine = B/D = 66.0/11.5 = 5.74 = 1/5.74
i.e. 4L of 85%v/v fortifying spirit will need to be added to 23L of must/wine, (@ 7.5%v/v alc.), to finish with a fortified wine of 19%v/v alcohol.
NOTE: The above numbers are for demonstration purposes only. Your actual numbers will vary but they will be close.
- Add the required amount of alcohol that was calculated above to your pressed wine and move your carboy to a cool as possible location. Also add about 100 ppm of SO2 for a preservative and this also helps to stop the fermentation. I like to use an old fridge to chill the carboy and port down or a freezer would be better. Tip: Keep the alcohol to be added in a freezer until it is needed to assist in chilling the port wine. The quicker that you can chill the must the faster that the fermentation will stop.
- After 1 day the fermentation should be stopped and the gross lees will begin to settle out. I let it sit for a week or two on the gross lees and then I rack it.
Aging the Port
- At this point the port can sit in the carboy until it is ready to go into a neutral barrel for aging. You want to use an older barrel that is free from any off aromas and that no longer contributes any oak flavouring to wine. Typically this requires a barrel that is about 4-5 years old. Any barrel size will work, but generally something in the 50 to 100 liter range is best for most home winemakers.
- For best results the port should stay in the barrel for at least 2 years before bottling. Top up the barrel with port on a monthly basis.
- How long you keep the port in the barrel determines the style of port you want to make and is also dependant on your individual tastes.
- You can choose to make a true vintage port and only leave it in the barrel for two years then bottle all of it.
- You can take out about ¼ of the barrel every year and bottle that and then top up the barrel with fresh port. This creates a port with some tawny characteristics.
- You can leave the port in the barrel for 10 to 15 years or more to create a vintage tawny port.
I leave you with this quote by Percy Croft ‘Any time not drinking port is a waste of time’.